1. Field of the Invention
The invention relates to a battery manufacturing method, a battery, a pre-welding positive plate manufacturing method, and a pre-welding positive plate.
2. Description of Related Art
In related art, various secondary batteries, such as nickel-hydrogen secondary batteries, have been used as drive power sources for vehicles such as hybrid vehicles and electric vehicles and drive power sources for portable electronic devices such as laptop computers and video camcorders.
As one of such secondary batteries, for example, Japanese Patent Application Publication No. 2006-351376 (JP 2006-351376 A) describes a stack-type secondary battery, more specifically, a secondary battery having a battery case, and an electrode module that is disposed in the battery case and that is constructed of positive plates and negative plates alternately stacked on top of each other via separators. In this secondary battery, a lead portion (cathode collector portion) of each positive plate is welded to a cathode collector plate and a lead portion (anode collector portion) of each negative plate is welded to an anode collector plate.
Further, JP 2006-351376 A describes forming each positive plate by impregnating a foamed metal plate with an active material, and forming a lead portion (cathode collector portion) of the positive plate by compressing a portion of the foamed metal plate, which has not been impregnated with the active material, and then welding a nickel lead plate on one side of the compressed portion. Further, JP 2006-351376 A describes that, in order to connect the negative plates to the anode collector plate, triangular projections are formed at an end of each negative plate, the negative plate is arranged such that the projections are fitted in grooves formed in the anode collector plate, and the projections of the negative plate are joined to the grooves of the anode collector plate by delivering an electron beam from the outer side of the anode collector plate (see FIG. 4 of JP 2006-351376 A). Further, JP 2006-351376 A describes connecting each positive plate to the cathode collector plate in the same manner as described above, that is, forming triangular projections at an end of the lead portion (cathode collector portion) of the positive plate, arranging the positive plate such that the projections are fitted in grooves formed in the cathode collector plate, and then joining the projections of the positive plate to the grooves of the cathode collector plate by delivering an electron beam from the outer side of the cathode collector plate.
In the battery described in JP 2006-351376 A, as mentioned above, the lead portion (cathode collector portion) of each positive plate is formed by compressing a portion of the foamed metal plate (foamed nickel plate), which has not been impregnated with the active material, and then welding the lead plate (metal lead plate), which is made of nickel, etc., to one side of the compressed portion. Further, the negative and positive plates of the battery described in JP 2006-351376 A are manufactured by pressing. Therefore, when manufacturing each positive plate of this battery, a base board is prepared by impregnating the foamed metal plate with the active material, compressing a portion of the foamed metal plate, which has not been impregnated with the active material, and welding a nickel lead plate on one side of the compressed portion, and then the prepared base board is pressed (punch-pressed) into the shape of the positive plate.